A 4C/7.2F-10C/18F degree change in air temperature (increase or decrease) will cause a 1-3% horsepower change. These gaskets will lower the temperature of the intake manifold by at least 11C/20F and benefit both naturally aspirated & forced induction environments.

(heat shield washers are not included but are available for an additional $5.00 for a set of 9)

smallport gasket:

largeport gasket:

Test Vehicle information*The following conditions were consistent in both before and after states in collecting the proceeding data.Engine: 1.6 (naturally aspirated w/ 278 in/ex cams) small portState: 1100RPM idleCoolant temp: 76C/168FVaccum: 10 in.hgAmbient temp: 11C/52F

w/ Stock Intake Manifold Gasket (temperature reader held at ~24")

w/ Heat Screen Gasket (temperature reader held at ~24")**Temperature readings were taken from approximately the same location on the no. 1 cylinder intake runner.

Currently Discontinued Until Further Notice

Last edited by dr.occa on Fri Apr 08, 2016 5:36 am, edited 4 times in total.

Do you have the dyno numbers to back up your claim? I have thought about making these myself but after running numbers and doing research I decided the theory had to be bogus.

On the 4A each cyl consumes .4 liter every other revolution so we can say .2 L/rev. At 4000 RPM that is 800 liters per minute or 13.3 L/S. The runner for one cyl holds about .2 liters If I did my math right any one air molecule will spend about .015 seconds traveling down the runner. The air molecules right next to the runner surface are going to be the only ones able to conduct heat and even then only have .015 seconds to do so. So the question then becomes how much heat can 13.3 L/S conduct out of 70F ΔT traveling through a .2 lilter passage in about .015 seconds? I am not an engineer or mathematician so working out the solution would take me an embarrassingly long time but I just do not feel like these insulators can do much of anything. If you have dynos that support your claims I might be interested in throwing your product on my website if you would care to talk about it.

Unfortunately no Dyno numbers as of yet BUT they are in the works. It's not the cooling of air molecules but maintaining the density of them. You can liken it to your printer's ability to print in higher quality is contingent on its dpi or dots per inch. The more dots per inch the better resolution and quality of print.

Those dyno numbers will be forth coming but for the mean time there are some great articles by long time NHRA competitors and engineers pertaining to this subject that can be sourced with a little bit of searching. Hondata is a well known and respected name that are proponents on this topic.

dr.occa wrote:Unfortunately no Dyno numbers as of yet BUT they are in the works. It's not the cooling of air molecules but maintaining the density of them.

There are two ways to alter the density of air molecules. Pressure or temperature. One has to change for density to change.

Do you have any links to well researched information on the topic? I have spent quite a bit of time searching and have never found anything that looked educated or convincing. Hondata definitely isn't. They measure the manifold temp but what about intake temps at the head? What about dynos? What about independent studies by an unbiased party?http://www.hondata.com/heatshieldgasket.html#Details

dr.occa wrote:Unfortunately no Dyno numbers as of yet BUT they are in the works. It's not the cooling of air molecules but maintaining the density of them.

There are two ways to alter the density of air molecules. Pressure or temperature. One has to change for density to change.

Do you have any links to well researched information on the topic? I have spent quite a bit of time searching and have never found anything that looked educated or convincing. Hondata definitely isn't. They measure the manifold temp but what about intake temps at the head? What about dynos? What about independent studies by an unbiased party?http://www.hondata.com/heatshieldgasket.html#Details

You seem like a pretty intelligent person. I'm sure you don't really need either me or Corey to help you find answers but instead open a debate (and possibly unmask snake oil salesmen?). Dyno graphs forthcoming in the days ahead. If you don't mind, could we open this discussion in a separate forum section? That would be greatly appreciated.

I know I suggested we discuss this in a separate thread but just remember your physical science y'all:Higher temperatures result in lower air density because air molecules move faster and bounce further apart from one another in such conditions.

dr.occa wrote:I know I suggested we discuss this in a separate thread but just remember your physical science y'all:Higher temperatures result in lower air density because air molecules move faster and bounce further apart from one another in such conditions.

But how fast will it take change the temp of the intake charge 1 degree, due to the velocity of the air entering? I understand the lessening of the heat soak to the intake manifold, but does the air actually get hotter within the intake manifold? I would think the effect would be negligible due to the velocity of the intake charge.

WHP & AFR:(She ran really lean from 3000 -pretty much where the idle circuit hands off duties to the main circuit- to lean at 6000 and started seeing better AFRs by 6500 but still lean for a rotary)

Pulled her off the dyno and took her home to pull the stock gasket. Can't pull the intake without making a mess with the coolant due to 2 coolant ports just behind the intake flange (blocked off by my aftermarket 48 IDA intake mani). Didn't want to make a mess in Engine Logic's driveway either. Besides ambient temperature was increasing by the hour. We're in Texas; what did ya expect!?

Was watching for similar environmental conditions and came back Saturday morning, June 28th, 2014.

Kept everything exactly the same outside of the gasket and bolt washers. Even the carb jettings were exactly as before. Not even the jet screen cover was touched or blown clean of any debris. What coolant was lost was replenished during the gasket replacement. All conditions were exactly as before on the dyno as well.

WHP & Torque:

WHP & AFR:

So even with a slight increase in ambient temperature and a drop in barometric pressure (both condition changes being non conducive to increasing hp and not to mention rotaries tend to run pretty hot), the motor still picked up a whopping 1.3 WHP.

The gasket starts off as .125" thick but does shape to the mating surfaces when torqued to factory spec (the washers formed to their surfaces as well of course).

It's conceivable that there may be more potential gains using a thicker variation of the same gasket but that'll have to be for another time.

The last large port gasket was just sold. All that are left are a couple small port gaskets. Due to low interest, not sure if anymore will be made in the near future. Thanks to everyone who did take an interest.

dr.occa wrote:The last large port gasket was just sold. All that are left are a couple small port gaskets. Due to low interest, not sure if anymore will be made in the near future. Thanks to everyone who did take an interest.